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Thu Mar 18, 2010 12:43 pm

I have a peculiar sound emanating from (it seems) behind the instrument cluster of my 89 Carat. It started about a week or so ago, out of the blue, and it sounds very much like the sound you get with an alternator belt that needs tightening, or a bad bearing in a motor, in that it has that rotational sort of vibe vibe to it, but it's not quite the same. It's a little more chirpy than that, if you know what I mean. It's hard to describe. The sound appears and disappears, and gets louder and quieter seemingly at random. It does not seem to be correlated to anything that I can observe. You can hear it slightly, but not as well, from outside the vehicle and it seems to be centered in the same place - behind the instrument cluster, a bit towards the center of the dash.

My initial thought was that it might be the bearings on the radiator fan, but it happens whether or not the radiator fan is, in fact, running (and it has not been running much at all lately, with the cool temps we've had and generally driving at highway speeds). I also suspected the front blower motor briefly, but that was easy to ruel out - with the fan turned off, it still happens. I thought of an air leak around the windscreen seal, but it happens standing still. That also pretty much eliminated the rest of the suspension and steering parts and the speedo cable. I even thought about a tacho cable, but there isn't one as far as I can tell (it appears to be electronic).

Any thoughts?

My plan is to pull off the instrument cluster hood and take a listen to see if I can localize it more, and maybe do the same from underneath with the spare removed and the front with the grill taken off, but I'm really hoping one of y'all has experienced this before and can tell me "oh yeah - it's your frim-fram-a-jig" and how to fix it. :)

Thanks,
Doug

Thu Mar 18, 2010 1:16 pm

its the front heater, starting to go..check out bens place hes has a step by step w/ pics of dashboard removal

Thu Mar 18, 2010 1:25 pm

GBA 88West LA wrote: its the front heater, starting to go..check out bens place hes has a step by step w/ pics of dashboard removal

Well that stinks. :( Could certainly be worse, though. So what is the chirp coming from? I'm a bit surprised, particularly since the noise is there regardless of whether the front blower is running or not.

Doug

Thu Mar 18, 2010 1:32 pm

Speedo Cable?

Thu Mar 18, 2010 1:36 pm

if its the heater it shouldnt happen when heater is off position only on speeds one thru three

Thu Mar 18, 2010 1:37 pm

rsxsr wrote: Speedo Cable?

elsyr wrote: but it happens standing still. That also pretty much eliminated the rest of the suspension and steering parts and the speedo cable.

Thu Mar 18, 2010 1:37 pm

Tach?

Thu Mar 18, 2010 1:41 pm

Must be all the mice behind the dash.

Maybe there's a vacuum leak at the brake booster causing a whistling/squeaking sound? Just thinking out loud here.

Thu Mar 18, 2010 1:43 pm

Maybe try it with the engine off and key off. Then turn the key to on. I like the idea of a small vacumn leak. 8)

Thu Mar 18, 2010 2:00 pm

rsxsr wrote: Tach?

I was wondering about that, but looking at the diagrams in the Bently, the tacho appears to me to be electrical. If there's a tacho cable, I'm totally missing it in the manual.

Doug

Thu Mar 18, 2010 2:02 pm

Keane wrote: Must be all the mice behind the dash.

Maybe there's a vacuum leak at the brake booster causing a whistling/squeaking sound? Just thinking out loud here.

Now that's a thought (the brake booster, not the mice ;) ). I don't recall the noise being correlated to pressure on the brake pedal, but it might not be anyway.

Thu Mar 18, 2010 2:18 pm

I would guess the speedometer cable or speedometer head first, followed by a leaf or piece of paper stuck somewhere in the air ducts.

The speedo cable attaches to the left front grease cap. Remove the circlip and the grease cap and see if the noise goes away.

Thu Mar 18, 2010 2:19 pm

Wildthings wrote: I would guess the speedometer cable or speedometer head first, followed by a leaf or piece of paper stuck somewhere in the air ducts.

The speedo cable attaches to the left front grease cap. Remove the circlip and the grease cap and see if the noise goes away.

But would the speedo or speedo cable be making a noise like that at a dead stop? And would a leaf or something stuck in the duct be making noise with the blower off?

Thu Mar 18, 2010 2:20 pm

elsyr wrote: Wildthings wrote: I would guess the speedometer cable or speedometer head first, followed by a leaf or piece of paper stuck somewhere in the air ducts.

The speedo cable attaches to the left front grease cap. Remove the circlip and the grease cap and see if the noise goes away.

But would the speedo or speedo cable be making a noise like that at a dead stop? And would a leaf or something stuck in the duct be making noise with the blower off?

Nope to both.

Thu Mar 18, 2010 2:27 pm

Wildthings wrote: elsyr wrote: Wildthings wrote: I would guess the speedometer cable or speedometer head first, followed by a leaf or piece of paper stuck somewhere in the air ducts.

The speedo cable attaches to the left front grease cap. Remove the circlip and the grease cap and see if the noise goes away.

But would the speedo or speedo cable be making a noise like that at a dead stop? And would a leaf or something stuck in the duct be making noise with the blower off?

Nope to both.

That's what I figured.

Thu Mar 18, 2010 2:30 pm

Not sure is the instrument voltage regulator on these things can make noise. That is about all I can think up besides the brake booster.

Thu Mar 18, 2010 2:39 pm

Maybe brake or clutch pivot shaft.

or gerbils.

Thu Mar 18, 2010 2:41 pm

Well, I'll be damned - it may be the blower motor after all. I'd never noticed it in the ~4 months I've owned the van, but with the blower motor switch set to 0, the thing is still running at low low low speed and blowing a trickle of air. With the engine on, you can't hear it at all. When I bought the van, one of the first things I noticed was that the '3' on the fan switch had been covered over, and that if you did flip to that setting you got nothing ... I had assumed that the resistor for the third speed had burned out, but could it be that somebody rewired the switch to blow at speed 1 on 0? I mean, there should be NO fan motion on 0, right?

I did pop the instrument cover while I was in there, and the brake fluid is right where it should be. I also pulled the air director to get a better listen. Naturally, when I'm on the floor of the van with my ear up to the heater it won't get noisy for me - I'll try it again later.

Doug

Thu Mar 18, 2010 2:43 pm

Vanagonner wrote: Maybe brake or clutch pivot shaft.

or gerbils.

I don't think so - it'll make the noise without any movement of the brake pedal (and it's an automatic). If it turns out NOT to be the blower motor, then I may have to put some mousetraps in to eliminate the possibility of a rodent invasion. :shock:

Doug

Thu Mar 18, 2010 4:11 pm

You might check out these threads:

http://www.thesamba.com/vw/forum/viewtopic.php?t=395661

http://www.thesamba.com/vw/forum/viewtopic.php?t=386923